Open-Celled Foam Which Repels Water Vapor and a Process for Producing It

Abstract

The invention relates to a foam which has been made hydrophobic/oleophobic and comprises a foam matrix having open cells and having an impregnation which is made up essentially of a polyvinylidene halide (co)polymer which may optionally comprise further substituents and, if appropriate, additionally a fluorocarbon resin and/or silicone resin. The invention further relates to a process for producing this foam.

1 . A foam which comprises a foam matrix having essentially open cells and having an impregnation which is made up essentially of a polyvinylidene halide (co)polymer which may optionally comprise further substituents and additionally a fluorocarbon resin and/or silicone resin. 
   
   
       2 . The foam according to  claim 1 , wherein the halide is a chloride or fluoride. 
   
   
       3 . The foam according to  claim 1 , wherein the foam matrix is made up of a melamine-formaldehyde polycondensate. 
   
   
       4 . The foam according to  claim 3 , wherein the ratio of melamine to formaldehyde for producing the foam matrix is from 1:1.2 to 1:4. 
   
   
       5 . The foam according to  claim 1 , wherein the foam matrix is a urea-formaldehyde polycondensate. 
   
   
       6 . The foam according to  claim 1 , wherein the foam matrix is an open-celled polyurethane foam. 
   
   
       7 . The foam according to  claim 1 , wherein the impregnation consists essentially of a mixture of the polyvinylidene halide (co)polymer and the fluorocarbon resin, the silicon resin or both, fluorocarbon resin and silicone resin. 
   
   
       8 . The foam according to  claim 1 , wherein the impregnation is made up of two separate layers which respectively comprise essentially fluorocarbon resin, silicone resin or both, fluorocarbon resin and silicone resin or the polyvinylidene halide (co)polymer. 
   
   
       9 . The foam according to  claim 1 , wherein the polyvinylidene halide copolymer is copolymerized with vinyl halide. 
   
   
       10 . A process for producing a foam according to  claim 1 , comprising
 (a) application of a dispersion comprising vinylidene halide (co)polymer and additionally a fluorocarbon resin and/or silicone resin to the foam or soaking of the foam with the dispersion,   (b) pressing of the foam together with the dispersion in order to introduce the dispersion into the pores of the foam and   (c) drying of the foam together with the dispersion at a temperature in the range from 40 to 100° C.,   with the steps (a) and (b) being carried out successively, firstly step (a) then step (b).   
   
   
       11 . A process for producing a foam according to  claim 1  comprising
 (a) application of a dispersion comprising vinylidene halide (co)polymer to the foam or soaking of the foam with the dispersion,   (b) pressing of the foam together with the dispersion in order to introduce the dispersion into the pores of the foam and   (c) drying of the foam together with the dispersion at a temperature in the range from 40 to 100° C.,   (d) application of fluorocarbon resin and/or silicone resin to the foam or soaking of the foam with fluorocarbon resin and/or silicone resin after the drying in step (c),   with the steps (a) and (b) being carried out successively, firstly step (a) then step (b).   
   
   
       12 . The process according to  claim 11 , wherein the foam together with the fluorocarbon resin, the silicone resin or both, fluorocarbon resin and silicone resin is pressed in order to introduce the resin into the pores of the foam, with the application or soaking of the foam with the resin and the pressing being carried out successively, and is, optionally subsequently dried at a temperature in the range from 40 to 100° C. 
   
   
       13 . The process according to  claim 10 , wherein the water is used as solvent for the dispersion. 
   
   
       14 . The process according to  claim 10 , wherein the dispersion comprises from 5 to 60% by weight of polyvinylidene halide (co)polymer. 
   
   
       15 . The process according to  claim 11 , wherein the water is used as solvent for the dispersion. 
   
   
       16 . The process according to  claim 11 , wherein the dispersion comprises from 5 to 60% by weight of polyvinylidene halide (co)polymer. 
   
   
       17 . The foam according to  claim 2 , wherein the foam matrix is made up of a melamine-formaldehyde polycondensate. 
   
   
       18 . The foam according to  claim 2 , wherein the foam matrix is a urea-formaldehyde polycondensate. 
   
   
       19 . The foam according to  claim 2 , wherein the foam matrix is an open-celled polyurethane foam. 
   
   
       20 . The foam according to  claim 2 , wherein the impregnation consists essentially of a mixture of the polyvinylidene halide (co)polymer and the fluorocarbon resin, the silicone resin or both, fluorocarbon resin and silicone resin.